If you don't have enough protection in the game, then this mod from winject should interest you. It allows you to take a police shield in one hand, which is excellent protection against bullets. With such a shield, you can easily attack the enemy without fear of dying under return fire.
The shield only works with a pistol and a baton.
Controls: "O" - get / remove the shield; "Insert" - script restart (must be used after character change).